Abstract for: Why Do We Slip in the Bathtub? - Explanation of Stock-Flow Failure Based on Systems with Life

Booth Sweeney and Sterman (2000) through their experiments with Bathtub Dynamics, relating to stock and flow models, report that irrespective of educational level, business background the subjects have a poor level of understanding of stock and flow relationships and time delays. Recently, Cronin, Gonzalez and Sterman (2009) ask the question, ‘Why don’t well-educated adults understand accumulation?’ Though accumulation is a fundamental process in dynamic systems, behaviour of simple stock-flow situations are not understood well by even students trained in mathematics or physics. Through a series of experiments Cronin et al. (2009) show that the poor performance is not explicable by inability to interpret graphs, lack of contextual knowledge, motivation, lack of feedback or cognitive capacity. They also show the presence of an erroneous heuristics called ‘correlation heuristics’. In this paper we explain this phenomenon applying what is called the Missing Middle Hypothesis (MMH) arising out of autopoietic understanding of cognition as put forward by Maturana and Varela (1980). Missing middle hypothesis deals with the question why human memory does not record the middle of the distribution of its experience in its environment. We also discuss how MMH can explain other human decision making pitfalls noticed by Kahneman and Tversky (1982).